The Texas coral snake has the traditional coloration associated with coral snakes: black, yellow, and red rings. It is capable of growing to 48 in in total length, but most are closer to. Males are typically smaller than females. It has smooth dorsal scales, a rounded head, and the eyes have round pupils. Albinistic and anerythristic specimens have been found in the wild. "Pastel" coloration has been noted, and completely black specimens, are known. The Texas coral snake is somewhat larger than the eastern coral snake, and has a somewhat larger venom yield.
Behavior
All coral snakes are shy, secretive animals, typically nocturnal. They spend most of their time hiding in leaf litter, under logs. They can be seen crawling on the surface, after heavy rains, when the nighttime temperatures rise above. When grabbed suddenly, or sometimes just when touched, they may thrash about, swing around, and bite. Sometimes they are calm, and then suddenly swing around and bite, for no apparent reason.
Diet
The primary diet of M. tener consists of other snakes, primarily earth snakes, and other small fossorial species. It is cannibalistic. It also occasionally eats small lizards, but the consumption of rodents by coral snakes is rare.
Other nonvenomous snakes resemble the Texas coral snake as a form of Batesian mimicry. In the United States ONLY, all three species of venomous coral snakes can be identified by the red rings contacting the yellow rings. A common mnemonic device is "red and yellow, kill a fellow".
Venom
Texas coral snake venom is a powerful neurotoxin, causing neuromuscular dysfunction. Until 2006, no deaths from coral snake bites had been reported since the 1970s in the United States. However, rare, fatal bites have occurred according to several scientific journals in the '80s and '90s. Because of the low profits, the production of coral snake antivenin has been discontinued for several years. Prior to the availability of antivenin, the fatality rate of coral snake envenomations has been estimated at 10%, and death was primarily due to respiratory or cardiovascular failure as a result of paralysis induced by the neurotoxic venom. Wyeth Pharmaceuticals, a wholly owned subsidiary of Pfizer, produced antivenin for the eastern coral snake, which can also be used for treatment of envenomation by the Texas coral snake. However, the last lot produced has an expiration date of January 31, 2020. A coral snake is proteroglyphous, meaning it has a pair of deeply grooved, semihollow, chisel-shaped, fixed fangs in the front of its upper jaw, through which the venom is injected and encouraged via a chewing motion. Coral snakes do not necessarily need to bite and hold on for a brief time to deliver a significant amount of venom. They expel venom quickly during extraction into collection media in the lab. Severe envenomations have occurred after a quick bite. Many bites from coral snakes do not inject any venom at all. A bite from any coral snake should be considered an extremely serious medical emergency, and medical treatment should be sought immediately, because symptoms of envenomation are known to sometimes delay manifestation for as long as 24 hours, but once present, often progress very rapidly.
Subspecies
The five recognized subspecies of M. tener are:
M. t. tener
M. t. fitzingeri
M. t. maculatus
M. t. microgalbineus
M. t. tamaulipensis
Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Micrurus. M. t. tener is found in both the US and Mexico, whereas the other subspecies are endemic to Mexico.
The Texas coral snake was once considered a subspecies of the eastern coral snake, Micrurus fulvius, but more recent research has determined that it has enough morphological differences to be considered its own species.
